A comprehensive geotechnical and geophysical assessment of the foundation sublayers in egypt’s new administrative capital

This study presents a comprehensive geotechnical and geophysical characterization of foundation sublayers in Egypt's New Administrative Capital, using thirteen Electrical resistivity Tomography (ERT) profiles with seismic velocity data from seventeen Shallow seismic refraction sites and three strategically selected Multichannel Analysis of Surface Waves (MASW) locations. The MASW sites were selected based on geoelectric profiles that reflect the complete types of lithologic variability across the study area, ensuring representative shear wave velocity (Vs) measurements. Resistivity results delineating four major subsurface units: a variable unit of sand, clay, and rock fragments; a limestone unit, a clay unit, and a sandstone unit. Seismic data enabled the calculation of key geotechnical parameters such as: rigidity modulus, Poisson's ratio, Young's modulus, and bulk modulus, revealing zones of high competence in the northeastern and northwestern parts, and incompetent materials in the central and southwestern parts of the study area and fairy to moderately competence between them. Material competence was assessed using the concentration index, material index, and stress ratio, which collectively divided the area into zones of slightly, moderately, and highly competent materials. Bearing capacity analysis showed ultimate and allowable bearing capacity values high in the eastern and southern zones, while central regions exhibited reduced capacities. These results provide a good assessment for site-specific foundation design and highlight the value of using geoelectric and seismic methods in complex urban planning.